Self-cleaning filter

ABSTRACT

Improved self-cleaning filter, comprised of a casing ( 1 ) with an entry ( 2 ) for water towards an encircling chamber ( 5 ), a filtering element based on a plurality of grooved disks ( 10 ), an axial passage ( 14 ) in the breast of these disks and an axial exit ( 9 ) for clean water. The filtering element ( 10 ) is completed in its lower end by a flap ( 11 ) that closes the axial passage ( 14 ) in the backward movement of water during cleaning, forcing it to go through side collectors ( 15 ) unaffected by the flap ( 11 ) and in which established are windows ( 16 ) for the exit of water, obliquely oriented in a side direction to make the disks ( 10 ) rotate during cleaning, also oblique in a vertical direction to take advantage of the separation between the disks ( 10 ) and distributed helically ( 15 ), the support tower ( 6 ) of these disks completed in a retractile rammer ( 21 ).

OBJECT OF THE INVENTION

The present invention IMPROVED SELF-CLEANING FILTER refers to a seriesof improvements introduced into self-cleaning filters, for examplefilters for water cleaning, where the self-cleaning process is carriedout by means of a temporary reversal in the direction of the water flowthat intersects it.

The improvements for the invention have as an objective to minimizewater consumption during this self-cleaning process, improving thecleaning conditions of the filtering disks, especially in the face ofresiduals of an adherent type, and facilitating their disassembly in therecurrent and indispensable manual deep cleaning operations.

BACKGROUND OF THE INVENTION

The State of the Art, in what refers to self-cleaning filters, hasundergone a rapid evolution in past times, fundamentally due to thedevelopment of its utilization in watering applications.

Known by the public in general is the advance reached in achieving abetter usage of water resources, especially in regions characterized bya natural shortage of water. To this sense, we can cite as examples ofthis type of mentioned techniques, watering by sprinklers and wateringby micro-spray. All of these modern techniques achieve a high degree ofwater usage. On the other hand, it is also obvious that more and moreone turns to the use of poor quality waters, which frequently haveimpurities, and although these do not constitute an inconvenience intraditional watering techniques, they can be a serious problem inwatering installations with sprinklers and micro-spray. For this reason,it is necessary to place filters, which prevent as much as possible theentry of impurities, brought by the water flow to the described wateringinstallations with sprinklers and micro-spray.

The problem that arises then, with the usage of filters, is the onederived from the necessary cleaning and maintenance proceduresassociated to its operation, to eliminate the impurities accumulated inthem.

With regards to this, self-cleaning filters have been known for sometime, in which, starting from a cylindrical sensitive casing, placedinside the same are two coaxial chambers, a perimeter and an axial one,connected to each other through a plurality of filtering disks providedwith grooves on their faces that are sometimes radial and sometimesoblique, so that when these disks are superimposed onto each other, thementioned grooves become conduits of a reduced caliber, which are whatconfer to the device the filtering effect.

U.S. Pat. No. 4,707,259, describes a counter-current flow filterincluding a plurality of ring shaped filter elements placed one on topof the other forming an assembly of a generally cylindrical shapefastened to a cylinder, which are cleaned by counter current flow of aliquid through the mentioned elements. The filter includes a stoppingmechanism to prevent the filter elements from vibrating during thefiltration, but when the filter is being cleaned the stopping mechanismallows the filter elements vibration.

In European Patent EP0347477 a disk filter including a housing defininga fluid inlet and a fluid outlet is described. The filter elementdefines an upstream surface communication with the fluid inlet and adownstream surface communicating with the fluid outlet with a hollowvolume interior limited by the disks that form the filter element.

In this type of filter, the encircling or external chamber is coupled tothe corresponding water entry, generally radial, while the axial chamberis connected in turn to the flow exit for the filtered water, generallyin an axial position, so that the water, conveniently pressurized,reaches the perimeter chamber in the first place, passes through thedisks to reach the axial chamber, producing its filtering, and finallyleaving the filter through the axial exist of the same.

Obviously the mentioned filtering conduits are damaged with dirt andwith time, for which periodic cleanings of the same are necessary, forthis reason it is also common to reverse the water flow direction, sothat clean water enters through the flow exit, passing between the disksand carrying the dirt deposited in the same towards the usual entrymouth. Also known, to facilitate this maneuver, is that the disks beseparated during the self-cleaning maneuver, to facilitate thedetachment and carrying of the dirt.

This singularity makes these filters widely used, especially incountries where the cost of the manpower necessary for cleaning thefilter is high, thereby those that are self-cleaning are preferred.

This structure brings an extensive and varied problem that centersmostly on the following aspects:

During the cleaning or self-cleaning phase an excessive consumption ofwater exists, for which the entire circulating flow, when reversed,becomes waste water.

In sewage waters and in those with a high degree of particles insuspension, the number of necessary cleanings is very high, and togetherwith the waste of water in each cleaning, which is mentioned in theprevious paragraph, makes the system very expensive.

The fixture rigidity of the mechanisms constituent of the filter to thecorresponding support casing, hinders its disassembly when it isnecessary to effect a manual deep cleaning, a maneuver that obviouslymust be repeated cyclically.

When the pollutants of the water to be filtered are of an adherent type,for example algae remains, the simple reversal of the flow causes aninsufficient cleaning of the filtering disks, which forces shorterself-cleaning cycles, and more frequent manual deep cleaning operations.

For all of this, it is evident that the self-cleanings filters known inthe State of the Art leave a considerable number of inconvenienceswithout solving, for which improvements have been devised that make upthe present improved self-cleaning filter that is described next.

DESCRIPTION OF THE INVENTION

With regards to the previously explained, the improvements that theinvention proposes have been conceived in order to fully solve in asatisfactory manner the previously expressed problems, in theirdifferent commented areas.

Thereby, the present improved self-cleaning filter is composed of abasic structure, similar to other filters of this type, constituted byan external chamber, to which the water entry is coupled, in whoseinterior is located an axial chamber that communicates with the conduitor exit mouth, both chambers being defined by a framework of disks,found inside this external chamber, and the interior chamber isconstituted by the interior of the disks or filtering rings.

One of the peculiar characteristics of the present self-cleaning filteris constituted by the support tower of the disks, that makes up thementioned disk framework, whose end corresponding to the exit of cleanwater is completed by a seat base for a flap that acts as a stopper forthe axial passage of the water, a flap that tends to act in a closingmanner through a spring, conveniently impeded to allow opening the sameduring the normal flow of water when the filter acts as such, butautomatically causing a closing action when the flow reversal takesplace during the self-cleaning.

This flap is framed by a perimeter alignment of collectors, preferablyin fours, that are not affected by the same and that establish thebackward moving water flows during the self-cleaning phase, thecollectors having for such a purpose orifices or windows for the exit ofwater specially directed towards the disks, allowing to cleanly select asmall jet for each disk, with the object of achieving greatereffectiveness in the self-cleaning phase of the water flow directionreversal.

This way, the water flow during the self-cleaning is considerablyreduced with regards to the water flow under filtering conditions, thisflow change automatically taking place in the flow reversal forcleaning.

In the same way, another singular characteristic of the present improvedself-cleaning filter is constituted because the support tower of thefiltering disks is completed in its end opposite the mentioned flap witha rammer that keeps the filtering disks conveniently separated duringthe filtering, this rammer being axially moveable against the tension ofa spring, so that this mechanism pressing the disks, before an externalaction of any type, for example before a pneumatic pressure against thementioned spring, allows the necessary separation between the filteringdisks, to improve their cleaning, but all of this without producing avariation in the longitudinal dimension of the filtering element, whichwill be exactly the same in both the filtering phase and in the cleaningphase, which allows an easier coupling of the same to any casing type,since it does not require anything beyond the closing pressure of thelatter to remain stable in its interior, allowing an extremely quick andsimple extraction.

Besides the aforementioned, in the present improved self-cleaning filterit is provided that the orifices or windows of the self-cleaningcollectors are adapted in a tilted position, so that the jets of watergenerated in each one impact obliquely on the disks, achieving twodifferent and complementary effects, on the hand the elevation andconsequent separation between the disks, and on the other the cleaningof the same, the first effect specifically due to the vertical componentand the second to the horizontal component, tangential to the externalsurface of the filtering disks framework, to the force vector that setsthe water flow.

It has also been provided that the windows be of a rectangular shape andthat, considering the collectors in their entirety, they describe ahelical path, which, on the one hand, contributes to the rising effectof the disks and, on the other, makes the cleaning water sweep theentire surface of the same.

The special incidence angle of the cleaning flows on each disk, alsocauses the rotation of the same, making the disks rotate freely removingthe impurities and particles registered in the filtering process, whichalso contributes to improving the cleaning conditions.

Finally, and in accordance with another characteristic of the invention,it is provided that in the perimeter chamber defined on the outside ofthe disks, to which the water has access at first during the filteringphase, established, in the entry end will be helical deflectors thatgenerate, due to the dynamic flow of water, a high turning speed of thesame inside this chamber, that leads, by centrifugal force, to adisplacement of the solid particles in suspension towards the casingwall, that is to say, to a lodging of the same with regards to thefiltering block, which directly affects in an important way the time ittakes to obstruct the filtering element, or what is the same, it makesthe number of necessary cleanings lessen considerably, as theseparticles in suspension remain in the external limits of this chamber,without reaching the filtering rings.

DESCRIPTION OF THE DRAWINGS

To add to the description that is being rendered and with the object ofhelping to better understand the characteristics of the invention, inaccordance with a preferable example of a practical execution of thesame, accompanying as an integral part of this description is a set ofdrawings with an illustrative and non-limiting nature, where thefollowing has been represented:

FIG. 1. View of a schematic representation in a side elevation of animproved self-cleaning filter carried out according to thecharacteristics object of the present invention, with its casing cutopen to show with more clarity a part of its interior structure.

FIG. 2. View in a side elevation, similar to that of FIG. 1, of the samefilter in the previous figure in a longitudinal section and with theflow indicating arrows of the self-cleaning phase, that is to say in aphase opposite the one shown in the previous figure.

FIG. 3. Detail of the lower part of the filter from the previous figure,but in an opposite situation to that of FIG. 2, that is to say, in afiltering situation.

FIG. 4. Detail of the upper part of the filter in FIG. 2, but in anopposite situation, that is to say, in a filtering situation.

FIG. 5. Detail in a cross-section of the filtering element at the levelof one of the disks that partake in the same.

FIG. 6. Enlarged detail in section of one of the self-cleaningcollectors, where represented are the vectors corresponding to the jetsof water acting on the filtering disks and the decomposition of thesevectors when impacting on the latter.

FIG. 7. Diagram corresponding to the cascading operability of the jetsof water that emerge from the different collectors during theself-cleaning process.

PREFERED EMBODIMENT OF THE INVENTION

From these figures one can observe how an improved self-cleaning filter,rendered according to the characteristics of the invention, isstructured, like any conventional filter of this type, with the help ofa cylindrical casing (1), where in one of the ends an entry isestablished (2) for the water to be filtered, casing (1) that isenhanced by a cover (3) conveniently fixed to it by means of a perimeterflange (4) or by any other means, defining the casing (1-3) is a chamber(5) in whose breast lies the filtering group manifested in a tower (6)that through its end close to the entry (2) is completed in a base (7)coupled tightly to a neck (8) that frames the exit conduit (9), in anaxial position, establishing on the mentioned tower (6) a plurality ofdisks (10) providing oblique grooves in their faces, as especiallyobserved in FIG. 5, so that between these disks, convenientlyinter-coupled, as observed in FIGS. 1 and 4, the passage of water isproduced for the filtering of the same, according to the arrowsrepresented in FIG. 3.

Well then, starting from this basic structure and according to theinvention, the base (7) of the tower (6), constitutes the seat for aflap (11) qualified to stop the axial passage (14) through which thewater, after passing through the disks (10), is directed towards theexit (9), flap (11 ) that tends to permanently act in a closing mannerthrough a spring (12) arranged between this flap (11) and a fixedsupport (13), so that the tension of the mentioned spring (12) is enoughto displace the flap (11) against the seat (7) into a closing action,when the flow of the water is reversed, as shown in FIG. 2, during thecleaning phase, whereas under normal filtering usage conditions, thepressure with which the water reaches the axial passage (14) is enoughto counter the spring's tension (12) so that the flap (11) adopts anopening position allowing the free passage of water towards the exit(9).

In the tower (6) a plurality of collectors (15) participate, four in thepractical execution example represented in the figures, each one ofwhich is extended downwards with regards to the seat base (7), so thatit is not affected by the closing flap (11), these collectors (15)acting as a retreating mechanism for the cleaning water, limiting theflow to its own section, for which, under such conditions, the flap (11)maintains the axial passage (14) closed.

Each one of these collectors (15) has a longitudinal alignment ofwindows (16) that, as one especially observes in FIG. 5, adopt anobviously tilted position with regards to the radius corresponding tothe filtering element, and with the purpose that the jet of watergenerated through each hole or groove (16) impacts obliquely on thedisks (10), forcing them into a revolving movement when they areseparated from each other, as will be seen later on.

Also, the mentioned orifices (16), as observed in FIG. 6, also adopt atilted position with regards to the disk planes (10), so that thecorresponding jet of water (17) impacts on the lower face of these disks(10), unfolding their vector into two vectors, a vector parallel to thelower face of the disk, that causes the sweeping and consequently thecleaning of the same, and another perpendicular vector that causes aseparation between the disks, adopting these the floating situationshown in FIG. 2.

It has also been provided that the mentioned orifices or windows (16)adopt a rectangular shape so water curtains are generated due to thespin of the disks (10) and because of the location of the orifices orwindows (16) in the different collectors (15). The windows (16) are notat the same height as the immediate upper or lower window (16) from thenext collector (15), in such way the windows (16) in differentcollectors (15) create an imaginary helical path around them (15). Sucha lay out results in the different water curtains generated by thewindows (19) creating a helical water curtain that wets all the disksuniformly. The helical water curtain makes the cleaning operation easierand more effective helping the disk separation and avoiding any diskremaining dry and dirty.

To allow this axial separation between the disks (10), according to theposition represented in FIG. 2, the tower (6) is provided to becompleted in its upper end by a head (19), axially connected to thistower by an axial rod (20) where a rammer is telescopically set (21),acting as a piston that under normal filtering conditions rests on thepile of disks (10), as shown in FIGS. 1 and 4, keeping these disks in asituation of maximum closeness to each other, through a spring (22) thattends to displace this rammer (21) towards the disks, while during theself-cleaning phase and, for example, when applying pressure inside thechamber defined between the end of the tower (6) and the rammer (21),the tension of the spring is countered (22) and the rammer rises (21)towards the situation of separation between disks (10) shown in FIG. 2.

Finally, and as a complement to the described structure, in the lowerend of the encircling chamber (5), immediately following the entry (2)and as a perimeter continuation of the base (7) of the tower (6),established are a plurality of helical deflectors (24) that force thefluid, through its own dynamic flow, to a high turning speed, accordingto the arrows represented in FIG. 1, which in turn originates, aspreviously said, that through centrifugal force the solid particles insuspension that previously dirtied the filtering element determined bythe set of disks (10), are deposited on the casing (1-5) of the filter,not coming close to said filtering element and achieving a substantiallengthening of intervals between successive self-cleanings, with theconsequent water savings that this implies, besides the filter being outof service less time.

On the other hand, and for manual cleanings in a long term, it is enoughto open the flange (4) and to remove the cover (3) of the casing, sothat the filtering element, without requiring any other disassemblingmaneuver, is directly accessible without more than “unplugging” thetower (6) of the casing neck (8).

It is not considered essential to make this description more extensiveso that any expert in the subject understands the scope of the inventionand the advantages that are derived from the same.

The materials, shape, size and position of the elements will besusceptible to variations, provided this does not imply an alteration inthe essence of the invention.

What is claimed is:
 1. A self-cleaning filter comprising: a casing inside of which is a filtering framework including a plurality of piled up grooved discs supported on a seat base; an encircling section between said pile of discs and said casing, said encircling section configured to receive a fluid during a filtering phase from a radial entry located in one end of the casing, the fluid passing through said discs towards an axial exit conduit; a rammer that under normal filtering conditions acts, by action of a spring, on the pile of discs tending to keep them linked resting on said seat base, said rammer being retractile against said spring; a chamber defined between a fixed part and said rammer so that when a reverse flow of fluid enters the filter by said axial exit conduit the fluid reaches said chamber to counter tension of said spring and release the filtering discs allowing an axial separation thereof, the reverse flow providing a self-cleaning effect, by discharging the fluid in jet forms so that the jet fluid impacts obliquely, tangential to an external surface of the discs and to make the discs revolve; a wide axial free passage defined in said pile of discs through which fluid to be filtered after passing through said discs is directed towards said axial exit conduit; a flap tending to permanently close said wide axial free passage acting on said seat base through action of a spring arranged between said flap and a fixed support; a plurality of collectors placed around said wide axial free passage and surrounded by said pile of discs, said collectors extending from said seat base to a proximity of said axial exit conduit so that said collectors are not affected by the closing flap which under said conditions maintains said wide axial free passage closed, said reverse flow circulating through said collectors which limit the flow by its own section, and reaching said chamber; a longitudinal alignment of windows in each of said collectors for the exit of cleaning fluid in the form of jets against the lower face of the discs; and a supporting tower of said discs including said seat base, a plurality of connectors to which said supporting tower is attached, and said fixed support linking said connectors and delimiting said chamber.
 2. A self-cleaning filter, according to claim 1, wherein the windows for the exit of cleaning fluid from the collectors adopt a tilted position in an upwards direction, so that the jet of fluid that leaves through the windows impacts on a lower face of the discs separating them due to an upward direction of the jets.
 3. A self-cleaning filter, according to claim 1, wherein the windows for the exit of cleaning fluid from the collectors have a rectangular cross-section.
 4. A self-cleaning filter, according to claim 1, wherein the windows of the collectors are progressively displaced in height in different collectors so that sweeping of the jets of fluid of the different collectors is helical, said helical paths of cleaning fluid contributing to improve cleaning effectiveness on said revolving discs.
 5. A self-cleaning filter, according to claim 1, wherein the supporting tower includes a lower base, a supporting tower flap, and a head which with a corresponding mobile rammer form a group coupled to the casing.
 6. A self-cleaning filter, according to claim 5, wherein the casing further includes a removable cover fixed to the casing by a perimeter flange, so that the filtering group remains fixed in the casing in a working position and directly accessible through said removable cover.
 7. A self-cleaning filter, according to claim 1, further comprising, in said encircling section a plurality of helical deflectors that establish for the fluid a high-speed helical movement in the encircling section. 